Hey guys have I am a 5th year apprentice and given the job of changing the oil on 4 CVHF 700 tonners and 2 2550 CDHF dualees , have done the purge filters and and oil filters but not sure on how to do the oil , Im a visual person and reading the operation and maintenance manual dosent tell me very much besides do it though the oil charging valve , I know this is simple for you guys but I'm just looking for some direction so that I dont get air into the chiller.